Non-contact, such as capacitive or inductive or directional, coupler technology has been suggested as a method of improving the performance and the functionality of data and communications interconnect busses. However, few practical means have been provided by which these capacitively or inductively or directionally coupled buses can provide multi-point to multi-point connections between various circuit packs connected to the bus.
U.S. Pat. No. 3,619,504 to De Veer et al. issued Nov. 9, 1971 discloses a high speed data transmission network employing directional coupling elements that are spaced along a transmission line to couple information from the transmission line to taps. De Veer discloses transmission lines with a single source and a plurality of sinks or, conversely, a single sink and plurality of sources. De Veer also discloses a dual multiplex system for interconnecting two source circuits with two sink circuits. Source elements are respectively connected to transmission lines. Spaced along each transmission line are two directional couplers, one connected to each sink circuit. Thus, a sink circuit is connected to more than one stub line and is capable of receiving signals originating from both sources.
U.S. Pat. No. 5,638,402 to Osaka et al. issued Jun. 10, 1997, discloses a bus transceiver or databus. It employs capacitive and inductive coupling between bus connector lines. Further, it discloses a plurality of two way circuits coupled through a non-contact bus.
U.S. Pat. No. 5,365,205 to Wong issued Nov. 15, 1994 discloses a backplane databus utilizing directional couplers. The transmission line or conductive loop is terminated by a termination resistor in the circuit card which includes the driver for the transmission line.